An easier way see what those files are -

Type or paste about:cache in the address bar and press Enter/Return. In the disk section, select List Cache Entries

What can I do about them, I take it I'm being tracked for I noticed this when I started using a VPN with a foreign server and my location was detected.

I disabled add-ons and all else I can find and still they appear.

The tiles one as in the image. I do not have or ever had an amazon account or Trivago yet alone use them.

The one which you are pointing to is related to data for Top Sites.

In Settings -> Home -> Firefox Home Content be sure all sub-category (shaded) boxes are de-selected

(I only have Web Search selected)

I created another profile and noted those tiles. I always have 'about blank' on all pages and unchecked parent boxes. It seems to be a privacy bug, eg; Amazon and Trivago. 'Parasites'

I followed your instruction and yes it got rid of them however, as above I had the parent boxes unchecked and as in the image you would think it would disable the children boxes, bug or intentional which would not be very good for privacy leaning browser, especially with parasites like Amazon and Trivago.

What about the others do you have them created on your browser. The new test profile I created also created some.

The language pack is self explanatory. Info about the "remote settings content signature" appears to be related to Safebrowsing.

Why would it be self explanatory, I booted a copy of Linux Mint and it's cache remains at 0kBs on start-up. I have no idea how it all works but to me if you can clear all data, cookies and cache files for privacy purposes then anything in that folder that gets constantly re-created is a privacy risk for tracking, file name or contents. For example, if I as a layman would have to have those files there I would introduce random obfuscation, even if the file name was a must, the contents would be obfuscated so that no two files are ever the same throughout millions of browsers.

But then, as above, Linux FF doesn't seem to need them? This is wrong for I looked at another copy of Linux with FF and strict privacy and it's similar, around 56.0kbs. I don't know, for it seems the more privacy you chose the more that gets created in the cache.

To me this is a bug and privacy breach: -Tiles, Amazon and Trivago hence parent check boxes not disabling child boxes. -Recreation of identical files on start-up when Linux seems to work fine.